North Korea Loses Its Link to the Internet

While perhaps a coincidence, the failure of the country’s computer connections began only hours after President Obama declared Friday that the United States would launch a “proportional response” to what he termed an act of “cybervandalism” against Sony Pictures.

Over the weekend, as North Korean officials demanded a “joint investigation” into the Sony attacks and denied culpability — an assertion the United States rejected — Internet service began to get wobbly. By early Monday, the Internet went as dark as one of those satellite photographs showing the impoverished country by night.

Experts who monitor the health of the global Internet called it one of the worst North Korean network failures in years. But American officials who had described over the weekend how they were intensely focused on the country’s telecommunications connections through China — and how they had asked the Chinese government for help in cutting off the North’s ability to send malicious code around the world — declined to discuss what befell those connections.

“I guess accidents can happen,” one said in a very brief telephone conversation.

A State Department spokeswoman, Marie Harf, told reporters on Monday, “We aren’t going to discuss, you know, publicly operational details about the possible response options,” adding that “as we implement our responses, some will be seen, some may not be seen.”

There was no definitive way, at least in the short term, to determine whether the connection had been cut, overloaded, or attacked. And security experts cautioned that there could be many reasons for Monday’s failure. North Korea could be pre-emptively taking its systems offline to prepare for an attack, some said.

Chris Nicholson, a spokesman for Akamai, an Internet content delivery company, said it was difficult to pinpoint the origin of the failure, given that the company typically sees only a trickle of Internet connectivity from North Korea. The country has only 1,024 official Internet protocol addresses, though the actual number may be a little higher. That is fewer than many city blocks in New York have. The United States, by comparison, has billions of addresses.

But when the sun rose in North Korea on Tuesday morning, the few connections to the outside world — available only to the elite, the military, and North Korea’s prodigious propaganda machine — were still out.

As the morning wore on, however, some connections began to come back after a blackout of nearly 10 hours, though there was still very little traffic, according to CloudFlare, an Internet company in San Francisco.

Those connections to the outside world are managed by Star Joint Ventures, the country’s state-run Internet provider, and almost all of them run through China Unicom, China’s state-owned telecommunications’ company. They were not operative on Monday, but the causes could include a cyberattack by the United States — something American officials have said they would be hesitant to do if it meant infringing on Chinese sovereignty.

It is also possible China Unicom simply unplugged its neighbor. Internet monitors said a maintenance issue was unlikely to have caused such a prolonged failure.

Doug Madory, the director of Internet analysis at Dyn Research, an Internet performance management company, said that North Korean Internet access first became unstable late on Friday. The situation worsened over the weekend, and by Monday, North Korea’s Internet was completely offline.